Unify logging process

common/common.go

@@ -16,15 +16,20 @@ func AppendIfUnique(appendee string, array []string) []string {
 	return append(array, appendee)
 }
 
-// Prints each element, along with a small ASCII tree
-func PrintTree(strarr []string) {
+// Generates a small ASCII tree for the given string array
+func GenerateTree(strarr []string) string {
+	tmpstr := ""
+
 	// iterate over each element
 	for iter, elem := range strarr {
 		// check if we got the last element
 		if iter < len(strarr) - 1 {
-			fmt.Printf("|- %s\n", elem)
+			tmpstr = fmt.Sprintf("%s|- %s\n", tmpstr, elem)
 		} else {
-			fmt.Printf("'- %s\n\n", elem)
+			tmpstr = fmt.Sprintf( "%s'- %s\n", tmpstr, elem)
 		}
 	}
+
+	// Return constructed (grown?) tree
+	return tmpstr
 }

ethernet/arp/arp.go

@@ -3,7 +3,7 @@ package arp
 import (
 	"fmt"
 	"git.darknebu.la/maride/pancap/common"
-	"github.com/fatih/color"
+	"git.darknebu.la/maride/pancap/output"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 	"log"
@@ -52,15 +52,12 @@ func ProcessARPPacket(packet gopacket.Packet) error {
 
 // Print a summary after all packets are processed
 func PrintARPSummary() {
-	headline := color.New(color.FgRed, color.Bold)
-	headline.Println("ARP traffic summary")
-	printTrafficStats()
-	headline.Println("ARP LAN overview")
-	printLANOverview()
+	output.PrintBlock("ARP traffic summary", generateTrafficStats())
+	output.PrintBlock("ARP LAN overview", generateLANOverview())
 }
 
-// Constructs an answer regarding the ARP traffic
-func printTrafficStats() {
+// Generates an answer regarding the ARP traffic
+func generateTrafficStats() string {
 	var tmparr []string
 
 	// Iterate over all participants
@@ -82,11 +79,11 @@ func printTrafficStats() {
 	}
 
 	// And print it as a tree
-	common.PrintTree(tmparr)
+	return common.GenerateTree(tmparr)
 }
 
-// Prints an overview over all connected devices in the LAN
-func printLANOverview() {
+// Generates an overview over all connected devices in the LAN
+func generateLANOverview() string {
 	var tmparr []string
 
 	// iterate over all devices
@@ -95,7 +92,7 @@ func printLANOverview() {
 	}
 
 	// And print it as a tree
-	common.PrintTree(tmparr)
+	return common.GenerateTree(tmparr)
 }
 
 // Returns the arpStats object for the given MAC address, or creates a new one

ethernet/dhcpv4/dhcp.go

@@ -1,7 +1,7 @@
 package dhcpv4
 
 import (
-	"github.com/fatih/color"
+	"git.darknebu.la/maride/pancap/output"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 )
@@ -50,13 +50,8 @@ func HandleDHCPv4Packet(packet gopacket.Packet) error {
 
 // Print summary after all packets are processed
 func PrintDHCPv4Summary() {
-	headline := color.New(color.FgRed, color.Bold)
-	headline.Println("DHCP Network Overview")
-	printNetworkSummary()
-	headline.Println("DHCP Requests")
-	printRequestSummary()
-	headline.Println("DHCP Responses/Offers")
-	printResponseSummary()
-	headline.Println("DHCP Hostnames")
-	printHostnames()
+	output.PrintBlock("DHCP Network Overview", generateNetworkSummary())
+	output.PrintBlock("DHCP Requests", generateRequestSummary())
+	output.PrintBlock("DHCP Responses/Offers", generateResponseSummary())
+	output.PrintBlock("DHCP Hostnames", generateHostnamesSummary())
 }

ethernet/dhcpv4/hostnames.go

@@ -39,8 +39,8 @@ func checkForHostname(dhcppacket layers.DHCPv4) {
 	// None found, means client or server doesn't support Hostname option field. Ignore.
 }
 
-// Prints the list of all hostnames encountered.
-func printHostnames() {
+// Generates the list of all hostnames encountered.
+func generateHostnamesSummary() string {
 	var tmparr []string
 
 	// Construct meaningful text
@@ -72,7 +72,7 @@ func printHostnames() {
 	}
 
 	// and print it as a tree.
-	common.PrintTree(tmparr)
+	return common.GenerateTree(tmparr)
 }
 
 // Adds the given hostname to the hostname array, or patches an existing entry if found

ethernet/dhcpv4/network.go

@@ -140,14 +140,16 @@ func formatDate(rawDate []byte) string {
 	return formattedDate
 }
 
-// Prints the summary of relevant DHCP options
-func printNetworkSummary() {
-	fmt.Printf("Subnet Mask: %s\n", formatIP(networkSetup[layers.DHCPOptSubnetMask]))
-	fmt.Printf("Broadcast: %s\n", formatIP(networkSetup[layers.DHCPOptBroadcastAddr]))
-	fmt.Printf("Router: %s\n", formatIP(networkSetup[layers.DHCPOptRouter]))
-	fmt.Printf("DNS Server: %s\n", formatIP(networkSetup[layers.DHCPOptDNS]))
-	fmt.Printf("NTP Server: %s\n", formatIP(networkSetup[layers.DHCPOptNTPServers]))
-	fmt.Printf("Lease Time: %s\n", formatDate(networkSetup[layers.DHCPOptLeaseTime]))
-	fmt.Printf("Renewal Time: %s\n", formatDate(networkSetup[layers.DHCPOptT1]))
+// Generates the summary of relevant DHCP options
+func generateNetworkSummary() string {
+	// It's also possible to use strings.Builder here, but it produces code which is longer than this solution :shrug:
+	summary := fmt.Sprintf("Subnet Mask: %s\n", formatIP(networkSetup[layers.DHCPOptSubnetMask]))
+	summary = fmt.Sprintf("%sBroadcast: %s\n", summary, formatIP(networkSetup[layers.DHCPOptBroadcastAddr]))
+	summary = fmt.Sprintf("%sRouter: %s\n", summary, formatIP(networkSetup[layers.DHCPOptRouter]))
+	summary = fmt.Sprintf("%sDNS Server: %s\n", summary, formatIP(networkSetup[layers.DHCPOptDNS]))
+	summary = fmt.Sprintf("%sNTP Server: %s\n", summary, formatIP(networkSetup[layers.DHCPOptNTPServers]))
+	summary = fmt.Sprintf("%sLease Time: %s\n", summary, formatDate(networkSetup[layers.DHCPOptLeaseTime]))
+	summary = fmt.Sprintf("%sRenewal Time: %s\n", summary, formatDate(networkSetup[layers.DHCPOptT1]))
+	return summary
 }
 

ethernet/dhcpv4/request.go

@@ -15,8 +15,7 @@ func processRequestPacket(dhcppacket layers.DHCPv4) {
 	requestMAC = common.AppendIfUnique(dhcppacket.ClientHWAddr.String(), requestMAC)
 }
 
-// Prints the summary of all DHCP request packets
-func printRequestSummary() {
-	fmt.Printf("%d unique DHCP requests\n", len(requestMAC))
-	common.PrintTree(requestMAC)
+// Generates the summary of all DHCP request packets
+func generateRequestSummary() string {
+	return fmt.Sprintf("%d unique DHCP requests\n%s", len(requestMAC), common.GenerateTree(requestMAC))
 }

ethernet/dhcpv4/response.go

@@ -15,8 +15,8 @@ func processResponsePacket(dhcppacket layers.DHCPv4, ethernetpacket layers.Ether
 	addResponseEntry(dhcppacket.ClientIP.String(), dhcppacket.YourClientIP.String(), dhcppacket.ClientHWAddr.String(), ethernetpacket.SrcMAC.String())
 }
 
-// Prints the summary of all DHCP offer packets
-func printResponseSummary() {
+// Generates the summary of all DHCP offer packets
+func generateResponseSummary() string {
 	var tmpaddr []string
 
 	// Iterate over all responses
@@ -31,7 +31,7 @@ func printResponseSummary() {
 	}
 
 	// Draw as tree
-	common.PrintTree(tmpaddr)
+	return common.GenerateTree(tmpaddr)
 }
 
 // Adds a new response entry. If an IP address was already issued or a MAC asks multiple times for DNS, the case is examined further

ethernet/dns/answer.go

@@ -62,29 +62,31 @@ func processDNSAnswer(answers []layers.DNSResourceRecord) {
 	}
 }
 
-// Prints a summary of all DNS answers
-func printDNSAnswerSummary() {
+// Generates a summary of all DNS answers
+func generateDNSAnswerSummary() string {
+	summary := ""
+
 	// Overall question stats
-	fmt.Printf("%d DNS answers in total\n", numAnswers)
-	fmt.Printf("%s records\n", generateDNSTypeSummary(answerType))
-	fmt.Printf("%d unique domains of %d base domains, of which are %d private (non-ICANN) TLDs.\n", len(answerDomains), len(answerBaseDomains), len(answerPrivateDomains))
+	summary = fmt.Sprintf("%s%d DNS answers in total\n", summary, numAnswers)
+	summary = fmt.Sprintf("%s%s records\n", summary, generateDNSTypeSummary(answerType))
+	summary = fmt.Sprintf("%s%d unique domains of %d base domains, of which are %d private (non-ICANN) TLDs.\n", summary, len(answerDomains), len(answerBaseDomains), len(answerPrivateDomains))
 
 	// Output base domains answered with
 	if len(answerBaseDomains) > 0 {
-		fmt.Println("Answered with these base domains:")
-		common.PrintTree(answerBaseDomains)
+		summary = fmt.Sprintf("Answered with these base domains:\n%s", common.GenerateTree(answerBaseDomains))
 	}
 
 	// Output private domains
 	if len(answerPrivateDomains) > 0 {
-		fmt.Println("Answered with these private (non-ICANN managed) domains:")
-		common.PrintTree(answerPrivateDomains)
+		summary = fmt.Sprintf("%sAnswered with these private (non-ICANN managed) domains:\n%s", summary, common.GenerateTree(answerPrivateDomains))
 	}
 
 	// Check for public and private IPs
-	fmt.Printf("Answered with %d public IP addresses and %d private IP addresses\n", len(answerPublicIPv4), len(answerPrivateIPv4))
+	summary = fmt.Sprintf("%sAnswered with %d public IP addresses and %d private IP addresses\n", summary, len(answerPublicIPv4), len(answerPrivateIPv4))
 	if len(answerPrivateIPv4) > 0 {
-		fmt.Println("Private IP addresses in answer:")
-		common.PrintTree(answerPrivateIPv4)
+		summary = fmt.Sprintf("%sPrivate IP addresses in answer:\n%s", summary, common.GenerateTree(answerPrivateIPv4))
 	}
+
+	// Return summary
+	return summary
 }

ethernet/dns/dns.go

@@ -1,7 +1,7 @@
 package dns
 
 import (
-	"github.com/fatih/color"
+	"git.darknebu.la/maride/pancap/output"
 	"github.com/google/gopacket"
 	"github.com/google/gopacket/layers"
 )
@@ -27,9 +27,6 @@ func ProcessDNSPacket(packet gopacket.Packet) error {
 
 // Print a summary after all DNS packets were processed
 func PrintDNSSummary() {
-	headline := color.New(color.FgRed, color.Bold)
-	headline.Println("DNS Request Summary")
-	printDNSQuestionSummary()
-	headline.Println("DNS Response Summary")
-	printDNSAnswerSummary()
+	output.PrintBlock("DNS Request Summary", generateDNSQuestionSummary())
+	output.PrintBlock("DNS Response Summary", generateDNSAnswerSummary())
 }

ethernet/dns/question.go

@@ -51,22 +51,25 @@ func processDNSQuestion(questions []layers.DNSQuestion) {
 	}
 }
 
-// Prints a summary of all DNS questions
-func printDNSQuestionSummary() {
+// Generates a summary of all DNS questions
+func generateDNSQuestionSummary() string {
+	summary := ""
+
 	// Overall question stats
-	fmt.Printf("%d DNS questions in total\n", numQuestions)
-	fmt.Printf("%s records\n", generateDNSTypeSummary(questionType))
-	fmt.Printf("%d unique domains of %d base domains, of which are %d private (non-ICANN) TLDs.\n", len(questionDomains), len(questionBaseDomains), len(questionPrivateDomains))
+	summary = fmt.Sprintf("%s%d DNS questions in total\n", summary, numQuestions)
+	summary = fmt.Sprintf("%s%s records\n", summary, generateDNSTypeSummary(questionType))
+	summary = fmt.Sprintf("%s%d unique domains of %d base domains, of which are %d private (non-ICANN) TLDs.\n", summary, len(questionDomains), len(questionBaseDomains), len(questionPrivateDomains))
 
 	// Output base domains asked for
 	if len(questionBaseDomains) > 0 {
-		fmt.Println("Asked for these base domains:")
-		common.PrintTree(questionBaseDomains)
+		summary = fmt.Sprintf("%sAsked for these base domains:\n%s", summary, common.GenerateTree(questionBaseDomains))
 	}
 
 	// Output private domains
 	if len(questionPrivateDomains) > 0 {
-		fmt.Println("Asked for these private (non-ICANN managed) domains:")
-		common.PrintTree(questionPrivateDomains)
+		summary = fmt.Sprintf("%sAsked for these private (non-ICANN managed) domains:\n%s", summary, common.GenerateTree(questionPrivateDomains))
 	}
+
+	// And return summary
+	return summary
 }

output/output.go

@@ -0,0 +1,52 @@
+package output
+
+import (
+	"fmt"
+	"github.com/fatih/color"
+)
+
+const (
+	MaxContentLines = 50
+)
+
+// Prints a block of information with the given headline
+// If content is empty, printing the headline is omitted.
+// If the content is longer than MaxContentLines, content is cut.
+func PrintBlock(headline string, content string) {
+	// Print a newline to add some space between blocks
+	fmt.Println("")
+
+	// Check if we need to print a headline
+	if len(content) > 0 {
+		// We have content, we can print the headline
+		headlineColor := color.New(color.FgRed, color.Bold)
+		headlineColor.Println(headline)
+	}
+
+	// Cut to MaxContentLines if required
+	cutCont := cutContent(content)
+	fmt.Print(cutCont)
+}
+
+// Cut content after MaxContentLines lines
+func cutContent(content string) string {
+	numNewlines := 0
+
+	// iterate over every character
+	for i, c := range content {
+		// check if character is newline
+		if c == '\n' {
+			// it is, count occurrence
+			numNewlines++
+
+			// Check if we already hit our limit yet
+			if numNewlines == MaxContentLines {
+				// Found nth newline, return content up to this position.
+				return content[:i+1] // +1 to include the last newline as well
+			}
+		}
+	}
+
+	// We are done before reaching the cut limit; return the whole content
+	return content
+}